The report on special educational needs (SEN) provision for 16- to 25-year-olds found that spending on additional learning support varies from £6,600 to £17,900 per student in different areas.
It also found that only 25 per cent of local authorities provide parents with information on the outcomes achieved by individual education providers, while just 20 per cent offer any information on the quality of provision.
Learning difficulty assessments were found to be similarly patchy. According the NAO, assessments of young people’s needs vary in quality, and local authorities do not always consider the full costs of different placement options to the public purse.
Amyas Morse, head of the NAO, argued that the Department for Education (DfE) must improve its understanding of the cost-effectiveness of provision for 16- to 25-year-olds with additional needs.
"Giving the correct support to young people with special needs could help them lead more independent lives in the future and reduce longer-term costs to the public purse," he said.
"Yet a lack of understanding of the relationship between needs, costs and outcomes can lead to students not getting the right support, and risks compromising value for money."
Margaret Hodge, chair of the public accounts committee, called on government to tackle the "wide variations" between local authorities.
"We will want to explore with the DfE why these differences exist and what steps they are taking to ensure students are not disadvantaged by where they live," she said.
"The government spends £640m every year supporting around 147,000 students aged 16 to 25, but it doesn’t know whether this money is being well spent because of a lack of data on costs and outcomes. We will want to know how the department is addressing this weakness to get to grips with what works and secure best value for money."
A third of young people with SEN statements are not in education, work or training at the age of 18 – more than double the level for young people with no special educational need.
